1. Field of the Invention
The present invention relates to systems and methods for instruction processing and, more particularly, to systems and methods for performing multiplication processing of two maximally negative signed fractional numbers.
2. Description of Prior Art
Processors, including microprocessors, digital signal processors and microcontrollers, operate by running software programs that are embodied in one or more series of instructions stored in a memory. The processors run the software by fetching instructions from the series of instructions, decoding the instructions and executing the instructions. Processors, including digital signal processors, are conventionally adept at processing instructions that perform mathematical computations on positive fractional numbers specified as a data word. For example, some processors are adept at performing multiplicative operations, such as a 16-bit positive fractional number multiplied by another 16-bit fractional number. In general, multiplicative operations using 16-bit positive and negative fractional numbers produce a 32-bit result. The multiplication of two maximally negative 16-bit numbers produces a 33-bit result. The additional bit is required to represent the integer portion of the result. This type of multiplication employing two maximally negative fractional numbers requires an additional bit to represent the result of multiplying the two multiplied maximally negative 16-bit fractional numbers as well as a 17-bit DSP multiplier to produce the result. The utilization of a 17-bit DSP multiplier in a processor is expensive, while the utilization of a 16-bit DSP multiplier produces inaccurate results.
There is a need for a new method of multiplying two maximally negative fractional numbers using a 16-bit DSP multiplier to produce a 32-bit result. There is a further need for a new method of producing a result of two multiplied maximally negative fractional numbers represented correctly with 32-bits. There is also a need for a new method of identifying when two maximally negative fractional numbers are multiplied.